Metal-working machine



(No Model.) l P. BOKHOLS. 4 Sheets-Sheeh 1.

METAL WORKING MAGHNE. No. 602,062. Patented Apr. l2, 1898.

(No Model.) '4 sheets-sheen 2.

F. G. BGH-OLS. METAL WORKING MACHINE.

Patented Apr. 12, 1898.

filwiiinnnnunumt (No Model.) 4 sheets-sheet 4f F. G. vBU'IHIO'LS. v METAL WORKING MACHINE.

No. 602,062. 'Patented Apr. 12,1898.

Nirnn STATES TENT Erica,

M EnTAL-WORKING MACHINE.v

SPECIFICATION forming part of Letters Patent No. 602,062, dated April 12, 1898.

Application ined separat-Lr 20,1897. vserai No. 652,225. et man To all whom t may concern:

, Beit known that I, FRANK G. ECHOLS, a citizen of the United States, residing at Hartford,

in the county of Hartford and StateofConnec-` ticnt, have invented certain new and useful Improvements in .Metal-Working Machines, of which the following is a specification.

This inventionirelates to improvements in metal-working machines, and especially to automatic turning-lathes; and it has for its main object the provisionof a machine of VAthis type especially adapted for cutting away a portion of the teeth of an ordinary screwcutting tap to form the improved tap described and claimed in Patent No. 588,056, granted to me August l0, 1897. In the tap described in this patent the to'ol has an odd number of wings, and each wing has halftheusual number of teeth, one-half of allV the4 teeth of the tap being entirely removed, preferably by cutting out alternating peripheral teeth, all of the teeth being located in a single spiral from end to end of the tool.

For the purpose of forming .my improved tap from a tap of the ordinary construction I make use of a machine in the form of a turning-lathe, the principal features of which are a Work-holder and a tool-holder, one of which is rotatable preferably continuously, an intermittently effective cutting tool which is carried by the tool-holder and will usually be in the form of a chaser, and snitable means for automatically shifting one of the holders toward and from the other a plurality of times during each rotation of the rotary holder in order that the tool may be brought intermittently into position to -operate upon the work and. cut the latter at sepa-` rated points in its periphery.- In connection of the traveling holder; but in cutting taper- 'taps' this interval should vary in accordance witlithe taper of the tool. Hence in cutting away the teeth of taper-taps I make use,-in

connection with the instrumentalities herein- -before mentioned, of a guide disposed at an angle to the longitudinal axis of the workholder, the'angle 'of inclination of the guide correspon'ding,'of course, to the angle of taper of the tap. In the preferred construction of the machine the work-holder will usually travel along this' guide, so as to operate upon the tool at vprogressively-'varying distances from the longitudinal axis of the latter. In the preferred form thereof this guide will be adjustable in order that it may be shifted to any desired angular position and locked when set to correspond to the taper of -the tap upon which the tool or cbaser may be operatin g.

Forthe purpose of rendering the machine vautomatic in its action I may employ, in con- -at the end of the range of travel of the traveling holder. and for also reversing the direction of travel ofl such holder.

In the drawings accompanying and forming part of this specification, Figure l is a plan View of' a metal-working machine constructed in accordance with my improvements. Fig. 2 is a side elevation of the same. Fig. 3 is a sectional end elevation of the same with the tail-stock removed and shows the cutter in its operative position. Fig. 4 is a similar viewillustrating the cutter and the tool-holder thrown out of operation to permit alternateV teeth in the periphery of the tap to pass by the tool Without being-cnt. Figs. 5 and 6 are detail views of the tool-holder and slide-rest, and Fig.l 7 is a view of the tap as completed bythe machine.

' Similar characters designate like parts in all the figures of the drawings.

The several operative parts of mymproved machine will be mounted ordinarily upon the usual bed B, and many of these working parts are substantially similar to those found in metal- Working lathes in Acommon use. Among these may be mentioned the tail-stock T,' which slides on the vways 5 in the usual ICO manner, the head-stock II, the Work-spindle 6, and the lead-screw 7, supported for rotation in the bed of the machine and connected in the usual manner with the tool-carriage for imparting to the latter a traveling movement longitudinally ofthe bed of the machine. The lead-screw receives its movement from the spindle 6 through the spur-gear 6', secured to said spindle, which gear meshes with an idler-pinion S, from which movement is transmitted through an idler-pinion 9 and an idlergear 10 toa large spur-gear 12, secured to one end of the lead-screw. At the other end thereof the lead-screw is maintained in proper position and held against longitudinal movement by the usual nut 7. The devices just described constitu te the feeding means or feed mechanism for actuating the .tool-holder longitudinally of the machine.

For the purpose of rotating the Work-spindle 6 I prefer to make use of a pair of pulleys P and P, loosely mounted on the Workspindle and normally continuously rotated in opposite directions in the usual manner by means of belts. (Not shown.) For the purpose of bringing either of these pulleys into operative relation" with the Work-spindle to drive the latter I have shown herein a friction-clutch l5, splined to the Work-spindle and adaptedto slide thereon and having conical ends adapted to be received in corresponding openings in the inner faces of the loose pulleys P and P, it being obvious that when this friction-clutch is moved in the one direction or the other it may be brought into engagement with one or the other of said loose pulleys to turn the Work-spindle in a direction corresponding to the vdirection of rotation of said pulley.

The tool-carriage is designated in a general Way by C and is supported in the usual manner on the ways 5 for traveling movement longitudinally of the machine. The body portion of this tool-carriage is preferably composed of two members, the lower lof which is shown at 2O and embodies Ways similar'to those shown at 5 for carrying the upper or movable member 2l of said carriage. This upper member 2l is adjustable relatively to the lower member 2O by means of an adjusting-screw 22 for the purpose of properly regulating the position of the cutter at the beginning of the operation of the machine.

The tool-holder maybe of anysuitable construction, and it will be so mounted as to have a movement for shifting the cutting tool or chaser toward and from the Workholder, the movements of the tool-holder being so timed that said tool will be shifted back and forth a plurality of times during a single rotation of the rotary holder, which will be usually, and is in this case, the Work-holder.

`The movement of the tool-holder for carrying the cutter toward and `from the Workholder and into and out of engagement with the Work may be advantageously a reciprocating one, the tool-holder being mounted for oscillation on the upper member 21 of the` tion by holding means at 'the reduced end of the annulus-as, for instance, by a screwcap 27, a Washer or retaining-ring 28 being interposed between the screw-cap and the end of the iixed ring 26. In the construction shown the oscillatory tool-holder will be held normallyby means of a spring--as, for instance, the coil-spring 30-in the position shown in Fig. 3,With the cutter or chaser in its Working position. This springis seated in a vertical aperture or recess in the adjustable member 2l of the tool-carriage, its upper end engaging the Walls of a corresponding recess in the underside of a boss 3l, projecting from the tool-holder. The tool-holder also has at its opposite side an .arm 32, carrying an antifriction-roll 33, Which cooperates with a camshaft by means of which the tool-holder is oscillated, and which cam-shaft will be hereinafter described. The connection between the tool-holder and the'lead-screw by means of which traveling movement is imparted to said holder is obtained in this case by passing the lead-screw through a nut 34, formed as a fixed part of the member 20 of the toolcarriage.

As before stated, the cutting-tool which I prefer to employ is in the form of a chaser, and this Will usually be carried by a toolslide movable transversely of and mounted on. the tool-holder. The tool-slide is designated herein by s and is supported by the usual transverse Way on the tool-holder for reciprocation toward and from thelongitudinal axis of the Work-holder or Work-spindle of the machine. The cutting-tool will of course be adjustable longitudinally of this slide in order to position it properly with respect to the Work, especially at the beginning of each cnt. This cutting-tool or chaser is designated herein by c, and its adjustment may be obtained in any suitable manner. In the present instance I have illustrated a hand- Wheel 35 and an ad j listing-screw 36 for this purpose, the adj listing-screw being supported by the slide and having a suitable connection With the chaser-such, for example, as that shown in Figs. l, 3, and 4:.

For the purpose of oscillating the toolholder to carry the cutter into and outof its operative position With respect to the tap supported by the Work-spindle or tap-holder I make use of a cam-shaft carrying a circuit of Wipers, preferably equidistant from each other and corresponding in number to the IOO IIO

i' number of wings of the tap being formed.

This cam-shaft is illustrated at 40 and-issupported for rotation in suitablebearings on the4 machine, two of these bearings being on the tool-carriage, as shown at 41 and 42, and the third in the standard 45. In the. preferred construction this shaft is free to rotate, but has no longitudinal movement,and the wipers, by means of which the tool-holder is oscillated, are formed ona sleeve splined to the shaft 40, so as to move longitudinallythereof while rotating therewith, this sleeve being suitably guided between the cheeks of the bearings 41 and. 42. (See Figs. 1 and 5.) The cam-sleeve is designated by 46 and the wipers projecting therefrom by 46. It will be obvious that this mounting of the cam-sleeve and wipers is necessary in order to maintain them in the proper relation with the work-holder longitu` dinally of the machine, as the position of such holder will of course be constantly changing' during its traveling movement.

In the construction shown the cam-shaft 40 derives .its movement from the work-spindle, the latterhaving thereon a spur-gear 50, the teethof which mesh with those of an 'idlerpinion 51, (see Fig. 1,) which drives in turn a spur-gear 52, secured to the cam-shaft 40.' This gear-train is a two-to-one train in orderV that the tap may be rotated twice as fast as the'cam-sleeve carrying the wipers, this be# ing necessary for the purpose of permitting the tap to be rotated at such a rate as will' carry alternate Wings of the tool past the cutter and leave uncut alternate teeth in every turn of the tap, itbeing obvious, of course,

that the cutting-teeth and the interdentalV spaces formed by the removal of a portion of the teeth will alternate from endA to en'd of the spiral in which the teeth of the tap are located.

For the purpose of cutting the teeth of or-1 dinary taper-taps to form taps of the construction shown in the drawings, and more particularly described in my patent herein' before referred to, I employ, in connection with the devices -just described, a guide cooperative with the tool-slide to permit transverse movement of the latter in .accordance with the taper of the tap as the tool-carriage travels along the bed of the machine. This guide, which is designated in a general way by G, is preferably adjustable to differentv angles relatively to-theaxis of the workholder or tap-holder, and may be in the form of a cylindrical member or roll having re duced ends pivot-ally connected with thebed of the machine. These connections are preferably adjustable in such a manner as to per` mit angular adjustment of the guide. Said connections embody in the present instance a pair of slides 60 and 60.', mounted for slid` being employed for locking 'the slides to their Slide.

64" on the swivel-pin 64.

this scale show differentl angles of taper for different kinds of taps, and the guide may be 602,062 l v fg.

ways. These ways may be formed entstandards 63 and 63', bolted to the bed of the machine. The connections between the slides and the guide are preferably swivel-joints, two swivel-pins being shown at 64 and 64', respectively, in the eyes of which the reduced ends of the 'guide have a free sliding movement. The swivel-pinsof course turn freely in the slides 60 and 60.

As before stated, the tool-slide is intended to be guided in its movements by the rollr G, and for the purpose of controlling positively the position of the tool-slide the latter is preferably pivotallyconnected with a member slidable on the guide.

In the present case this' member. is in the form of a sleeve 70, en-

circling the guide and free to turn-thereon,

andit? has rising therefrom a round pin orV stud 7l, which passes through an aperture in a boss 72, projecting from one side of the tool- This pin may be headed up so' as to form in vertical direction a rather tight joint. It will be seen that, no matter 'what may be the angle to which the guideG is adjusted,

the sleeve 70, through-its pin 71,'Will turn freely in the boss of the tool-slide and willk carry the tool-slide with it assit re'cedes from and approaches the longitudinalV axis of the tap-holder. Thesleeve 70 preferably has a Vsecond boss 73, projecting therefrom substantially in the horizontal plane of the longitudinal axis of the guide, and thisboss lworks in a recessed guideway 74'r ina guide-arm 74', projecting laterally from the oscillatory toolholder. By means of this connection of the tool-holder with the sleeve 70 the latter'i's not only turned positively bythe former, but

is also -guided positively while it is being moved toward and from the axis of the tap.

In order to locate the guide G at the proper angle relatively tol the'wrk, I prefer to Vvemfploy aV taper-indicating scale, such as y30,-adjacent to the innerend of the guide, this scale being'intended' to coperate with a pointer The indications on set for any desired langle by loosening the being` understood that this binding-screw, 'as

well as the screw'62, should be screwed fast' before the machine is operated.

As it is intended that this machine'shall be' ,IOS

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automatic in its. action, I also make 'use of ysome suitable means' for throwing the toolholder to the position shown in' Fig. 4 and holding it there when the tool-holder reaches the end of its travel to the left, as seenin Fig. 1. 'Two stops are shown at 82 and 83 for this purpose, both being bolted to the bed of Athe machine, the former at the beginning of j for oscillating the tool-holder from its operative to its inoperative position.

I employ for this purpose a swinging hook in the form of a deadlock-cam Sehhaving a cam-shaped working face adapted to engage a bevel-faced stop 3l', projecting from the boss 3l into the path of the cam S4. (See Figs. 2, 3, and 4.) The hook 84 is pivoted on the upper portion 2l of the tool-carriage and may be held with itS end adjacent to the stop 3l by means of a fixed stop S5.

In order to reverse automatically the direction of rotation of the lead-screw at the beginning and at the end of the range of travel of the tool-carriage, I make use of any suitable automatic reversing means controlling the friction-clutch l5. A sliding shifter is shown at 8G for the purpose of operating ,this friction-clutch, said shifter being carried by arod 87, supported by the standards 45 and 45. This shifter is actuated by an oscillating shifting lever S8, controlled in its movements by a slide-rod 89, having a pair of adjustable stops 90 and 90', with which a stop 91 on the upper portion 2l of the tool-carriage is intended to engage at each end of the travel of the tool-carriage to shift the slide-rod 89 in the one direction or the other, and thereby through the intermediate connections clutch the member l5 to one or the other of the loose pulleys P and P. A

The operation of a machine constructed in accordance with my present invention as shown herein is as follows: A tap ot ordinary construction, which is to be changed into a tap of the type shown in my patent hereinbefore referred to, is first clamped in place in the usual manner between the head-stock and the tail-stock. The guide G is then adjusted at the proper angle and also secured iirmly in place by the binding-screws 62 and 62. It being understood that the tool-carriage is at the beginning of its range of travel, the cutting-tool or chaser c is then adjusted by means of the screw 22 to bring it to its eX- act position longitudinally of the tap, and its lateral position for taking the rst cut is determined by means of the hand-wheel 35. As soon as the tool and the tap are in their proper positions relatively to each other the machine is started in operation by the pulley P, and as the tap rotates the tool c takes the first cut in substantially the manner shown in Fig. 3, except that in that view the tool is shown cutting a tooth near the inner end of the tap and at the end of the range of travel of the toolcarriage instead of at the beginning of such movement. As the tap rotates and the tool cuts through the rst tooth thereof the calnsleeve carrying the Wipers 46 is also rotated slowly by the two-to-one train of gears connecting it with the work-spindle, the antifriction-roll 33 riding over the corresponding rest of the cam-sleeve until the cut is iinished, when the tool-holder will be operated by the proper Wiper 46 and the antifriction-roll 33 will ride up said wiper, and hence throw the chaser out of the path of the next succeeding tooth of the tap. As the tap rotates twice as fast as the cam-shaft, such next succeeding `tooth will pass by the cutting edge ot' the tool c and will not be cut by the latter, but instead the tap will turn far enough to skip one tooth and present the next one to the action ot the chaser, it being obvious that as such third tooth is brought into position the antifriction-roll 33 will ride down the opposite face of the wiper by which it was actuated and will lie on the next succeeding rest of the cam-sleeve, whereupon the operation j ust described will be repeated. While the cuttingtool, the cam-shaft, and the Work-holder are operating in the manner just described, the lead-screw is being continuously rotated by the gear-train connecting it with the workspindle, and the tool-carriage is progressively actuated toward the left-hand end of the machine, as seen in Fig. l. It should be understood, of course, that the movement ot' the feed-screw will be so timed as to cause the cutting-tool to come to the proper position as successive alternate teeth in the continuous spiral of the tap are presented to the action of its cutting edge. This action just described will be repeated and a cut taken for every other tooth of the tap until the end of the spiral in which the teeth are located is reached,it being apparent that as the tool-carriage continues its movement the cutter will be alternately oscillated into and out of engagement with the teeth of the tap, it operating to cut alternate teeth and to skip the intermediate teeth. Moreover, as the carriage moves, the sleeve will gradually recede from the .longitudinal axis of the tap to an extent previously determined by the taper of the tap and the angular position of the guide G and will carry the toolslide, and hence the tool,with it,thereby assuring a uniform cut for each tooth operated upon by the chaser. As soon as the last tooth of the tap is cut by the tool c the hook' 84 comes into engagement with the inwardly-projecting actuating member on the stop 83, and the cam-face of said hook rides up the bevelface of the stop 3l ot the tool-holder and engaging the upper side of said stop 31 shifts the tool-holder to the position shown in Fig. 4 and assumes a dead-lock position, in which it will lock the tool-holder, so as to maintain the latter and its tool out of operative relation with the tap. At the same time the stop 91 on the tool-carriage strikes the stop 90' on the slide-rod 89 and shifts the lever 88 to the opposite position from that shown in Fig. 1, and the pulley P is unclu tched from the workspindle, and the pulley P is clutched thereto. The direction of rotation of the parts being reversed,the tool-carriage will be carried back to its original position by the lead-screw, and as soon as it reaches its eXtreme right-hand position the actuating member 82 on the stop S2 will unhook the dead-lock cam S4 and permit the tool-holder to return the chaser to its eiective position. At the same time the stop IOO IIC

`90 is struck by the stop 91 and the slide-rod 89 shifted to the position shown in Fig. l to unclutch the pulley P and clutch the pulley P', whereupon the direction of rotation of the parts will be reversed again and the several devices will be in position for a new series of movements. The cutting-tool should now be adjusted by means of the hand-wheel 35, so as to bring the point ofthe chaser nearer to the tap to permit the chaser to take `another cut from the teeth which are to be removed, the several series of operations just described being continued until every other tooth in the tap is entirely cut away and the tap tpresents the appearance shown in Figs. l, 2, and 7.

Having described my invention, I claim--` l. The herein-described machine comprising a Work-holder; a tool-holdergautomatically-operative mechanism for rotating one of said holders; an intermittently-effective cutting-tool carried by the tool-holder; and means for automatically oscillating one of said holders toward and from the other a plurality of times during each rotation of the rotary holder and for maintaining a fixed interval between the holders while they are in their working positions, the parts being combined substantially as and for the purpose specified.

2. The herein-described machine comprising a work-holder; a tool-holder; automatically-operative mechanism for rotating one of said holders; means for imparting a feed movement to one of said holders; an inter-- mittently-effective cutting-tool carried by the tool-holder; and means for automatically oscillatin g one of said holders toward and from the other a plurality of times during each rotation of the rotary holder and for maintaining a fixed interval between the holders while they are in their working positions, the parts being combined substantially as and for the purpose specified. l v

3. The herein-described machine comprising a tool-holder; a tap-holder; automatically-operative mechanism for continuously rotating the tap-holder; anintermittentlyeffective cutting-tool carried by the toolholder; and means for automatically oscillating the tool-holder to carry said tool into engagement with alternate wings of the tap and maintaining it at a fixed distance from the axis of the tap while in its working position and for withdrawing said tool from engagement with intermediate wings of said tap, the parts being combined substantially as and for the purpose specified.

4t. The combination, with a work-holder and with a tool-holder, of means for rotating one of said holders; means for imparting a feed movement to the vtool-holder; an intermittently-effective cutting-tool carried by the tool-holder; a tool-holder guide disposed at an angle to the longitudinal axis of the workholder, and means for automaticallyvshifting one of said holders toward and vfrom theother i a plurality of times during each Yrotation of the rotary holder.

5. The combination,with a work-holder and with a tool-holder, of means for rotating one of said holders; means for imparting a feed movement to the tool-holder; an intermittently-effective cutting-tool carried by the tool-holder; a tool-holder guide adjustable -at an angle to the longitudinal axis of the work-holder; and means for automatically shifting one of said holders toward and from the other a plurality of times during each rotation of the rotary holder and for maintaining a fixed interval between the holders While they are in their working positions.

Y 6. The combination, with a tool -holder guide, of a work-holder; a tool-holder carried by said guide for oscillation toward and from the work-holder; work-holder-rotatin g means;

means for imparting a feed movement to the tool-holder; a cutting-tool carried by the toolholder; and automatic rotary tool-holder-oscillating means.

7.A The combination, with a tool -holder guide, of a work-holder; a tool-holder carried by said guide for oscillation toward and from the work-holder; work-holder-rotatin g means; means for imparting afeed movement to the tool-holder; a tool-slide carried by,and movable transversely of, the tool-holder; a cutting-tool lcarried by the tool-slide; and automatic rotary tool-holder-oscillating means.

8. The combination, with a tool -holder guide, of a work-holder; an oscillatory toolholder embodying a sleeve mounted to slideV on said guide and pivoted to the main portion of the tool-holder; work-holder-rotating means; means for imparting a feed movement to the tool-holder; a cutting-tool carried by the tool-holder; and automatic toolholder-oscillating means.

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9. The combination, with a work-holder, of i longitudinal axis of the work-holder; a cutting tool carried by the tool -holder; and means for automatically oscillating said toolholder toward and from the work-holder a plurality of times duringeach rotation of the work-holder and for maintaining the tool at a fixed distance from the axis of the workholder while in its working position.

l0. The combinatiomwith a work-holder, of work-holder-rotating means; a guide adapted to beset at an angle to the longitudinal axis of the work-holder; a tool-carriage; mechanism for imparting a feed movementfto the tool-carriage; a tool-holder carried v'by the tool-carriage; a tool-slide supported on the tool-holder to slide transversely thereof and guided by said guide; a cutting-tool carried by the tool-slide; and means for shifting said tool-holder toward and from the work-holder. 11. The combinatiomwithawork-holder, of

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Work-holder-rotating means; a guide adapted to be set at an angle to the longitudinal axis of the Work-holder; a tool-carriage; mechanism for imparting a feed movement to the tool-carriage; a tool-holder carried by the tool-carriage; a tool-slide supported on the tool-holder to slide transversely thereof; a sleeve slidable on said guide and movably connected with thetool-slide; a cutting-tool carried by the tool-slide; and means for shifting said tool-holder toward and from the Work-hold er.

12. The combination, with a Work-holder and means for rotating the same, of a. guide adapted to be set at an angle to the longitudinal axis of the Work-holder; a tool-carriage mechanism for imparting a feed movement to the tool-carriage; a tool-holder supported on the tool-carriage for oscillation transversely to the longitudinal axis of the Work-holder; a tool-slide supported on the Work-holder to slide transversely thereof and guided by said guide; a cutting-tool carried by the tool-slide; and means for oscillating said tool -holder toward and from the Work-holder.

13. The combination, With a Work-holder and with a tool-holder, of Work-holder-rotating means; means for imparting a feed movement to the tool-holder; an intermittentlyeffective cutting tool carried by the toolholder; means for automatically shifting said tool-holder toward and from the work-holder a plurality of times during each rotation of the Work-holder; and throw-out mechanism for automatically shifting the tool-holder out of action at a predetermined point in the operation of the machine.

v14. The combination, with a Work-holder and with a tool-holder, of Work-holder-rotating means; mechanism for imparting a feed movement to the tool-holder; an intermittently-effective cutting-tool carried by the tool-holder; means for automatically shifting said tool-holder toward and from the workholder a plurality of times during each rotation of the Work-holder; and for maintaining the tool at a fixed distance from the axis of the Work-holder while in its Working position and means controlled by the feed movements of the tool-holder for automatically reversing the operation of the feed mechanism.

15. The combination, With a Work-holder and With a tool-holder, of Work-.holder-rotating means; mechanism for imparting a feed movement to the tool-holder; an intermittently-effective cutting-tool carried by the tool-holder; means for automatically shifting -said tool-holder toward and from the Workholder a plurality of times during each rotation of the Work-holder; and for maintaining the tool at a fixed distance from the axis of the Work-holder While in its Working position and means controlled by the feed movements 0f the tool-holder for automatically reversing the operation of the feed mechanism at oppo` site ends of the range of travel of the toolholder.

16. The combination, with a Work-holder and with a tool-holder, of Work-holder-rotating means; mechanism for imparting a feed movement to the tool-holder; an intermittently-effective cutting-tool carried by the tool-holder; means for automatically shifting said tool-holder toward and from the Workholder a plurality of times during each rotation of the Work-holder; means for automatically reversing the operation of the feed mechanism and mechanism for automatically throwing the tool-holder into and out of action alternately at the beginning and at the end of its range of travel.

17. The combination, with a Work-holder and with an oscillatory tool-holder, of means for continuously rotating the Work-h older; an intermittently-effective cutting-tool carried by the tool-holder; and a rotary shaft carrying a plurality of Wipers cooperative with the tool-holder-for intermittently oscillating the latter away from the Work-holder during the rotation of said Work-holder and for maintaining the tool at a fixed distance from the axis of the Work-holder While in its Working position.

1S. The combination, With an oscillatory tool-holder and with a Work-holder, of means for continuously rotating the Work-holder; an intermittently-eective cutting-tool carried by the tool-holder; and a rotary shaft carrying a plurality of equidistant wipers coperative with the tool-holder for intermittently 0scillating the latter away from the Work-holder during the rotation of said Work-holder and for maintaining the tool at a fixed distance from the axis of the Work-holder while in its Working position.

19. The combination,\vith a tool-holder and with a tap-holder adapted to carry a tap having equidistant Wings, of means for continuously rotating the tap-holder; an intermittently-effective cutting-tool carried by the tool-holder; a rotary shaft carrying a plurality of equidistant Wipers, one for each wing of the tap, and cooperative with the tool-h older for intermittently shifting the latter away from the Work-holder during the rotation of said Work-holder; and a tWo-to-one gear-train between the Work-holder and said shaft.

20. The combination, With a Work-holder and with a tool-holder, of Work-holder-rotating means; means for imparting a feed movement to the tool-holder; an intermittently-effective cutting-tool carried by the tool-holder a tool-holder guide adj ustableat an angle to the longitudinal axis of the work-holder; a taper-indicating device for determining the angular position of said guide; and means for shifting the tool-holder toward and from the Work-holder and for maintaining the tool at a fixed distance from the axis of the Workliolder While in its working position.

FRANK G. ECIIOLS.

Titnesses:

F. I-I. RICHARDS, HENRY BissELL.

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